Author Topic: EEVblog #1007 - Is a $25 Multimeter Any Good  (Read 104206 times)

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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #225 on: July 19, 2017, 08:41:35 am »
When I "zapped" the AN8002, it was the higher energy generator that caused the damage you mention.  I don't record any of this testing in the spreadsheet.  It's more an FYI than anything.   

Yes. The meter had already failed (one of the clamp transistors exploded), you were unsatisfied with that result and felt the need for some fireworks so you turned up the power and switched it to an amps range. We all have days like that, it's nothing to be ashamed of.

Where are you sending the $10 if the 8008 fails the gun?
To any person who sends me $10 if it doesn't.
 

Offline Electro Detective

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #226 on: July 19, 2017, 08:43:20 am »
I know this is another $25 meter ($24.99 actually) but this coming Saturday, ALDI is offering this one.



Wonder what it would be like inside....?

I doubt anyone will see it on Saturday,

Fluke are sending their suits to Aldi Inc. tomorrow morning  >:( >:( >:( >:( >:( >:(



You might see a truckload of crushed ones at a local tip next Saturday  ;D

 
 
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #227 on: July 19, 2017, 08:43:49 am »
I agree Wilfred. When a person adds  :popcorn: to their post, it is a clear declaration of the intent to provoke, or troll.
Fungus is the king of popcorn here. With the frequency that he reaches for it he must have an expanding waistline.

But in my own mind I lean more towards devil's advocate than troll.  :popcorn:
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #228 on: July 19, 2017, 10:38:04 am »
I doubt anyone will see it on Saturday,

Fluke are sending their suits to Aldi Inc. tomorrow morning  >:( >:( >:( >:( >:( >:(

You might see a truckload of crushed ones at a local tip next Saturday  ;D

I'm sure they're plenty angry, but ... this is Europe.

 
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #229 on: July 19, 2017, 10:41:24 am »
I have been wondering before whether this forum would be an even better place if some of the emoticons were no longer offered. The popcorn-eater is one of them. I also find that the :-DD and :palm: can be quite offending, when they are used to comment on another member's posts.

To be 100% fair: They mainly get used because there's no middle-finger icon.
 
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Offline JanJansen

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #230 on: July 19, 2017, 11:00:56 am »
Aldi = € 14,99
I hope the 8008 is better, else i payed 1 euro to much.
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Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #231 on: July 19, 2017, 11:18:09 am »

To be 100% fair: They mainly get used because there's no middle-finger icon.

 :-DD

I'll take that as a "good" use of the laughing-myself-silly icon, rather than a "middle finger" use...  ;)
 

Offline Lightages

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #232 on: July 19, 2017, 02:56:14 pm »
...I believe that meters should be be rated falsely. That is all I have asserted in this thread.

Why should they be rated falsely?


Typo corrected.
« Last Edit: July 19, 2017, 03:00:51 pm by Lightages »
 

Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #233 on: July 19, 2017, 03:10:54 pm »
So, some kind of testing (even not independent) with clearly stated results would be great. I guess it would increase the price for the same meter however.
 

Offline G7PSK

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #234 on: July 19, 2017, 03:18:38 pm »
Seems to me that Fluke have created a monster with their safety advertising. All the cases I have read about where some person has been injured or killed by a flash over while using a test meter have been using a Fluke hand held meter, in my opinion and its is just mine it is not a good idea to attempt to test a high energy source with a meter in your hand, it is asking for trouble even with HRC fuses and blast shields in the meter the leads could still melt. Recently we had a power pole replaced and a new meter fitted, the engineers doing the work did not use a hand held Fluke meter they used a Megger/AVO meter which was of a size that precluded holding it in the hand, further they attached the leads with clips neutral first then live then turned the meter on. When testing the 33 KV side of the transformer they had 20 foot fiberglass poles on which the test meter.
Any of these meters that go to a thousand volts are good enough to test things like the HT on most tube amp's etc where the currents are low but even low voltages can be trouble when currents are high, when I was around 13 I connected an AVO meter to a single cell lead acid battery set on amp's range the trip blew but not before the leads were smoking hot and burnt me
But the real thing that everyone is forgetting is that it is not right to falsely make claims about a product you are selling and certainly here in the UK would be liable under the trade description acts.
 
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #235 on: July 19, 2017, 04:23:42 pm »
Seems to me that Fluke have created a monster with their safety advertising. All the cases I have read about where some person has been injured or killed by a flash over while using a test meter have been using a Fluke hand held meter

Maybe the death toll would be even higher if they weren't using Flukes.  :-//

Or maybe you only read about idiots who think owning a yellow meter allows them to ignore safety protocols.

it is not a good idea to attempt to test a high energy source with a meter in your hand, it is asking for trouble even with HRC fuses and blast shields in the meter the leads could still melt.

That's why Fluke adverts look like this:




And why shutterstock looks like this:



Yin + Yang = harmony in the world.
« Last Edit: July 19, 2017, 04:37:59 pm by Fungus »
 

Offline amspire

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #236 on: July 19, 2017, 04:40:17 pm »
I know this is another $25 meter ($24.99 actually) but this coming Saturday, ALDI is offering this one.



Wonder what it would be like inside....?
They don't give much information, but from what I can see, I will not be rushing to Aldi Saturday. morning. Four battery testing ranges. Transistor Hfe testing range. No mention of RMS. I think it is a cheap home handyman's multimeter. Couldn't see anything that might be interesting.
 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #237 on: July 19, 2017, 05:11:40 pm »
When I "zapped" the AN8002, it was the higher energy generator that caused the damage you mention.  I don't record any of this testing in the spreadsheet.  It's more an FYI than anything.   

Yes. The meter had already failed (one of the clamp transistors exploded), you were unsatisfied with that result and felt the need for some fireworks so you turned up the power and switched it to an amps range. We all have days like that, it's nothing to be ashamed of.

Where are you sending the $10 if the 8008 fails the gun?
To any person who sends me $10 if it doesn't.

Meter was damaged at the 3KV but the DCV function still worked.  I took the meter apart to see if it was a simple repair.  At that point the clamp was still fine.  The breakdown appeared to be in the selector switch.   The board does not have a lot on it and some of the functions were not showing the proper mode.  Conclusion, dead controller IC. 

If I could have repaired it, I would have stopped the testing and used it for another reference meter.  This is what happens with most of the repairable ones, or in the case of Dave's pre-production 121GW or the UNI-T 181A, I attempt to determine why they were damaged and see if they could be hardened.   Then I run them again.  In the case of the 121GW, it was damaged a second time but I got lucky and was able to repair it a second time and added one more TVS.  I then tested it again and it survived at the 6 and change KV level where I stopped testing. 

I ended up putting the meter back together and turned the generator up to max.  This damages it to where it no longer powers up. 

As I have previously explained, the 1/2 cycle simulator requires the low energy generator to work.  So the criteria is the meter is non-repairable and will break over at less than 5KV.   I applied one more transient with the lower energy generator to make sure it would break down in the volts mode.  I then gave it one transient off the 1/2 cycle in volts mode.  I switched the meter to mA and gave it one more cycle.  Then I took the meter back apart.  This is where you first see the extensive damage.   

I then give it one more transient with the cover off using the 1/2 cycle generator. 

I don't think I ever tried the Amps side.   I still have the meter sitting in the scrap box to recycle but I stole the shunt out of it when I ran all of them.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #238 on: July 19, 2017, 05:19:11 pm »
Where are you sending the $10 if the 8008 fails the gun?
To any person who sends me $10 if it doesn't.

If anyone would care to take Fungus up on his bet, I would be willing to run the meter.  I can't take the bet as if it does get damaged, someone may claim it was rigged.  It's also too far for me to go to meet up for a beer.  :-DD 
   
We could even run the grill ignitor first, so you could do a double down if you wanted.  :-DD   

Not sure if Fungus would take more than one bet.  Wouldn't hurt to ask if your all in the same area.  Seems like a good reason to meet up.     
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #239 on: July 19, 2017, 05:25:02 pm »
And why shutterstock looks like this:
[stock-photo-young-adult-electrician-builder-engineer-screwing-equipment-in-fuse-box-155918309.jpg]

Hey, he is even wearing a head torch, in case he blows up the switchboard and the lights go off.
Doesn't that count as safety precaution?   ::)


Edit: Also, according to the picture title, he is not measuring anything at all but "screwing the equipment"...  :palm:
« Last Edit: July 19, 2017, 05:37:43 pm by ebastler »
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #240 on: July 19, 2017, 05:31:25 pm »
I then gave it one transient off the 1/2 cycle in volts mode.  I switched the meter to mA and gave it one more cycle. 

Yep, you're right. I watched it again and the transistors blew after you zapped in in mA mode.
« Last Edit: July 19, 2017, 06:02:25 pm by Fungus »
 

Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #241 on: July 19, 2017, 05:38:57 pm »
And why shutterstock looks like this:
[stock-photo-young-adult-electrician-builder-engineer-screwing-equipment-in-fuse-box-155918309.jpg]

Hey, he is even wearing a head torch, in case he blows up the switchboard and the lights go off.
Doesn't that count as safety precaution?   ::)


Edit: Also, according to the picture title, he is not measuring anything at all but "screwing the equipment"...  :palm:

You can't do that with a fluke dmm, can you?
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #242 on: July 19, 2017, 05:46:36 pm »
Edit: Also, according to the picture title, he is not measuring anything at all but "screwing the equipment"...  :palm:

The screw appears to be 'hot', but ... luckily for him he was using a safety screwdriver.  :)

Unlike the guy below.
« Last Edit: July 19, 2017, 05:51:52 pm by Fungus »
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #243 on: July 19, 2017, 05:54:50 pm »
Edit: Also, according to the picture title, he is not measuring anything at all but "screwing the equipment"...  :palm:
You can't do that with a fluke dmm, can you?

I checked their 'accessories' page but couldn't find anything. Just a load of overpriced cables and meter pouches.
 

Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #244 on: July 19, 2017, 05:59:23 pm »
What would an electrician even use to screw those things? After checking the power.
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #245 on: July 19, 2017, 06:02:00 pm »
If anyone would care to take Fungus up on his bet, I would be willing to run the meter.  I can't take the bet as if it does get damaged, someone may claim it was rigged.  It's also too far for me to go to meet up for a beer.  :-DD 
   
We could even run the grill ignitor first, so you could do a double down if you wanted.  :-DD   

Tell you what: I'll up my bet to the price of a meter. If anybody thinks an AN8008 won't survive the grill igniter I'll get a meter shipped to joe and you can send me the purchase price via paypal if it lives.

Not sure if Fungus would take more than one bet.
Nope. Only one meter. First come, first served.

Wouldn't hurt to ask if your all in the same area.  Seems like a good reason to meet up.     

I'm in Spain. If anybody else lives in Valencia you're welcome to come along to my Arduino club this Friday. PM for details.
« Last Edit: July 19, 2017, 06:07:57 pm by Fungus »
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #246 on: July 19, 2017, 06:03:54 pm »
What would an electrician even use to screw those things? After checking the power.

This:
« Last Edit: July 19, 2017, 06:17:03 pm by Fungus »
 
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Offline G7PSK

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #247 on: July 19, 2017, 08:29:47 pm »
With the Fluke photo the man is holding a probe in each hand, so the meter blows up it's not in his hand the fuse go's the blast shields hold and what? the energy looking for somewhere to go jumps the probes to each of his hands, it's still not safe. As I stated in my earlier post the true professionals on power line's or other potential high energy use clip on probes on at least one end. And don't use hand held meters of any make.

 
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Online Specmaster

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #248 on: July 19, 2017, 10:28:47 pm »
With the Fluke photo the man is holding a probe in each hand, so the meter blows up it's not in his hand the fuse go's the blast shields hold and what? the energy looking for somewhere to go jumps the probes to each of his hands, it's still not safe. As I stated in my earlier post the true professionals on power line's or other potential high energy use clip on probes on at least one end. And don't use hand held meters of any make.
I think it may also be true that they would not be using a multimeter either, at the very least they would be using a dedicated voltmeter in order to minimise the chances of a high energy inrush surge to the instrument?
Who let Murphy in?
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #249 on: July 20, 2017, 06:02:58 am »
With the Fluke photo the man is holding a probe in each hand, so the meter blows up...

Why would it blow up? What mechanism?

A Fluke 117 (the meter in that photo)  is rated/tested for a CAT III 600V environment. That's a fairly precise specification about where it can be used safely.

...the fuse go's the blast shields hold and what?

The fuse won't go, because the meter isn't in a current measurement mode.

As I stated in my earlier post the true professionals on power line's or other potential high energy use clip on probes on at least one end. And don't use hand held meters of any make.

A "professional" will asses the environment and use an appropriate method.

If it's a CAT III 600V environment then a Fluke 117 is appropriate.

If it's a CAT IV 600V environment then a Fluke 117 isn't appropriate and you have to use something else.

« Last Edit: July 20, 2017, 06:09:19 am by Fungus »
 


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